The present study purposed to propose a PSL for Web-based computer graphic design that is suitable for industrial high school curriculum, reflects rapidly changing demands for communication in the contemporary society, and satisfies the desire for creative tools of students familiar with computer. For this purpose, we had a theoretical review based on literature on design curriculum in industrial high school, a PSL model for Web-based computer graphic design, and designed a Web-based computer graphic design instructional program focused on the development and visualization of ideas. The results show that students made a progress in all items related to the development and the visualization of ideas. Therefore, it is concluded that the collection and exchange of various types of information through the Web can give new diverse clues in developing design ideas. In addition, the use of the computer as a medium stimulates students’ interest in visualizing their ideas and expressing their thoughts using new tools. According to the result of analyzing students’ improvement in the development and visualization of ideas and their performance scored by the teacher in relation to a number of variables, students’ score was highly correlated with their improvement in the development of ideas (r=·0.864) as well as with their improvement in the visualization of ideas (r=0.887). That is, students who achieved high improvement in the development and visualization of ideas got a higher score in their design performance. This result suggests that students’ improvement is in a significant relation with their performance scored by the teacher and the teacher’s evaluation is highly reliable. In conclusion, the PSL for Web-based computer graphic design applied in industrial high school is considered to have positive effects on students’ development and visualization of ideas.